The need for more rapid laboratory diagnosis of Herpes simplex virus (HSV) infections has increased due to the prevalence of infection in immunocompromised hosts and the introduction of antiviral agents. Conventional methods require 1 to 10 for isolation and identification of HSV. We compared 3 rapid methods, the shell vial assay which we currently use, the VIDAS immunoassay, and the ENZO Pathogene HSV DNA probe. The ENZO product evaluation was terminated early in the study since we demonstrated it to be a relatively insensitive test. Attempts to improve it were unsuccessful. The VIDAS assay had a sensitivity of 77.4% and a specificity of 98.5% when compared to the shell vial assay. Although the sensitivity is too low to use this test exclusively, this method has use as a screening test to provide rapid results for the majority of specimens.